Automatic switch for use in telephone or like systems



Dec. 2, 1941. SAXBY 2,264,592

AUTOMATIC SWITCH FOR USE IN TELEPHONE OR LIKE SYSTEMS Filed March 26, 1938 IN VE Al TOR 1 ROBERT NORMAN SAX BY ATTY Patented Dec. 2, 1941 i UNETED ST AUTOMATIC SWITCH FOR.USE IN TELE- PHONE OR LIKE SYSTEMS ware a corporation of Dela- Application March 26, 1938,'Seri'al No. 198,189 In Great Britain April 16, 1937 2 Claims.

The present invention relates to automatic switches of the type used in telephone or like systems and is more particularly concerned with switches of the vertical and rotary type which employ a separate magnet for effecting each setting movement. The invention moreover is chiefly applicable to switches having so-called rectangular motion, that is to say, they are restored to their normal position by the renewed operation of the rotary magnet which advances the wipers clear of the banks after which they restore vertically and then rotate back under the banks to their normal position.

Arrangements have already been suggested whereby after switches of this type have been set in both directions they are adapted to restore their wipers backwardly to the rotary normal position in order that, for example, re-search of the level may take place. This type of release may be effected either by employing a release magnet particularly designed for the purpose or as disclosed in my Patent No. 2,028,689 granted Jan. 21, 1936, by the re-energisation of the vertical magnet. The invention is concerned with the latter method only.

On switches employing this so-called vertical magnet release it will be understood that the vertical pawl when operated after the switch has been set in both directions is arranged to engage with an extension arm of the rotary detent and move it out of engagement with the rotary ratchet member. When the wipers reach their rotary normal position the vertical ratchet member re-engages with the vertical holding detent thus preventing further release of the :-t.

wipers to their fully restored position. It will however be appreciated that at the same time the operated vertical pawl will also have to reengage with the vertical ratchet member since the vertical magnet energising circuit cannot conveniently be opened until the rotary off-normal springs restore when the wiper carriage reaches the rotary normal position. Hitherto the re-engagement of the vertical pawl in its operated position with the vertical ratchet member has been effected by the provision of a so-called subsidiary vertical pawl guide comprising a substantial flat metal strip which lies in the path of the vertical pawl in a position at the side of the vertical ratchet member and which is adjusted by bending so that it just allows the vertical pawl to fully engage with the vertical ratchet teeth during the normal vertical setting operation. It will be appreciated that if the vertical magnet is subsequently re-energised to bring about rotary release of the wipers, the subsidiary guide will limit the movement of the Vertical pawl to a position which it would take up in engaging with the ratchet teeth and it will therefore re-engage with the teeth when the wiper carriage restores to the rotary normal position.

In practice however the very critical adjustment required of the subsidiary pawl guide has made the maintenance of switches of this type rather diiiicult and it is the object of this invention to provide a means whereby under the above described condition the vertical ratchet can return to normal without having to reengage accurately with the vertical pawl.

According to the invention this is effected in that a guide member operated as soon as rotary movement takes place is arranged to move into the path of the vertical pawl and limit its travel so as to facilitate re-engagement of the pawl with its associated ratchet if the vertical magnet is energised when the wiper carriage reaches the rotary normal position.

The invention will be better understood from the following description of one method of carrying it into effect, reference being had to the accompanying drawing comprising Figs. 1 to 4. Figs. 1 and 2 show exploded and plan views respectively of the improved subsidiary pawl guide arrangement While Figs. 3 and 4 show part of the mechanism of a two-motion switch of the type in question with the subsidiary guide member incorporated thereon. Fig. 3 shows the position taken up by the movable elements of the guide member before the rotary setting of the wiper carriage and Fig. 4 shows the condition after one rotary step.

Referring now to Figs. 1 and 2 which show the constructional details of the arrangement, it will be seen that it comprises a fixed plate H] which is adapted to be secured to the switch frame by screws which pass through the holes H and I2. Mounted on the plate is a shaft l5 which is provided with a boss at the end nearer the plate so that a lever I3 and a plate l4 may rotate freely thereon while they are prevented from falling off by the washer'Zl which is pressed by the helical spring it against the end of the boss. The spring i6 is secured to the front end of the shaft and at its other end it loops into a slot 9 in the plate H! as shown more clearly in Figs. 3 and 4. The face of the plate l4 adjacent to the lever i3 is suitably grooved as shown by the dotted lines in Fig. 1 so that the latter may rotate over a limited arc independently of the plate between the shoulders I4 and I4". When lever I3 moves counter-clockwise its upper end engages the upper lug I4 on the back of plate I4 and carries that plate forward with it.

Referring now to Fig. 3, it will be seen that the tongue on the lever I3 is pressed by the helical spring I6 against the side of the vertical ratchet member I9 and it should be appreciated that it rests against the ratchet member in a position between the bottom of the ratchet teeth and the rotary ratchet hub 20, while the lower plate I!) is also arranged to clear this latter hub. The upper plate I4 of the subsidiary guide member takes up the position shown by gravity since it is unbalanced about its pivot while the lever I3 acts as a stop. During the vertical setting of the switch the vertical pawl I8 (shown in an operated position) can therefore engage the vertical ratchet member [9 under control of the vertical magnet armature II without fouling the subsidiary guide member.

When the switch makes the first rotary step as shown in Fig. 4, the lever I3 due to the tension of the spring 55 commences to rotate with the vertical ratchet and in so doing carries the plate I4 with it so that its left edge passes under pawl I8 before that pawl is disengaged from the teeth of ratchet I9. When the plate I4 reaches the position shown, its upper right-hand edge comes up against the frame of the switch mechanism and the rotation of both the plate and the lever is thereby arrested. In this position, which is maintained if the switch makes more than one rotary step, it will be seen that the plate I I is interposed in the path of the vertical pawl and lies in the same plane as the base of the teeth on ratchet I9.

If the vertical magnet is now energised to bring about rotary release of the wipers, the vertical pawl after completing a part of its normal travel engages with and slides along the plate I 4 and during this time it clisengages the rotary detent member in the manner described in said prior patent and clearly shown in Fig. 2 thereof. When the vertical pawl strikes the front stop (not shown), it jams between it and the plate I i which is of substantial construction and thereby remains in a convenient partly-operated position so that it will easily re-engage with the vertical ratchet member when the wiper carriage 22 restores to the normal position.

On reaching this position the vertical ratchet member I9 strikes the tongue of the lever I3 thereby restoring it to the position shown in Fig. 3. The plate I4 will remain locked due to the pressure of pawl I8 against the surface thereof until the vertical magnet is de-energised and withdraws the vertical pawl whereupon it will restore to the position shown in Fig. 3. It will be understood that on normal release after the full rectangular movement the vertical magnet will not be energised when the wiper carriage reaches the rotary normal position and the reengagemerit of the parts presents no difficulty. In this case the lever I3 and the plate I4 restore to normal together when the former is engaged by the vertical ratchet I9.

It will be seen therefore that the arrangement according to the invention provides a simple and eificient solution to the problems of rotary release on two-motion switches not provided with a separate release magnet.

I claim:

1. In an automatic switch having a wiper shaft with vertical and rotary motion and a vertical pawl and ratchet, in which the vertical pawl is disengaged from the vertical ratchet when the shaft is given a rotary movement, the provision of a guide member, means operated upon the initial rotary movement of the shaft about its vertical axis from a normal rotary position for moving said member into a position under said vertical pawl to cause the reengagement of said vertical pawl with its normal rotary ratchet when the shaft returns to said vertical position.

2. A guide arrangement for the vertical pawl of a vertical and rotary switch, which switch has a wiper shaft having a normal position and vertical and rotary movement therefrom and a vertical ratchet which is moved out of line with its pawl when the switch moves in a rotary direction, comprising a guide member pivoted adjacent the vertical pawl, an operating lever for the guide member normally held ineffective by the vertical ratchet while the switch is in its normal rotary position, means for operating said lever to move the guide member into the path of the vertical pawl when the shaft takes its first rotary movement, said guide member held in said path of the vertical pawl, until said shaft returns to its normal rotary position.

ROBERT NORMAN SAXBY. 

